mikejuby369 said: I am careful to download transactions only once the first day of the month prior to the opening of the market.
"Reconciliation would be much easier if the valuations would remain frozen at the end of the month until after I've completed all reconciliations".
It's not necessary to prevent the download of prices to make your investment account reconciliations easier.
When you're ready to reconcile; create an Investing > Portfolio Value report, for the account you're reconciling, as-of the date of the statement you're reconciling to.
Quicken will price the securities in that (and any) report using the available price that is closest to the date of the report ... but not later than the date of the report.
[And if the price Quicken uses is earlier than the date of the report, Quicken will show an asterisk by the price to denote that the price is an "estimate".]